Agriculture Reference
In-Depth Information
budding as late as
).
Grafting rootstocks with dormant scionwood in England is usually carried
out in March and cleft-grafting of established trees from mid-February to
June. Bench-grafting, carried out indoors, may be followed by two months
of callusing at approximately
November is successful (Kuden and Kaska,
◦
Cor
◦
C (Hartmann
et al.
,
days at
).
Budbreak: the buds of apples and pears enter into dormancy in autumn
and emerge from this when their winter-chilling requirement has been
satisfied and when subsequent ambient temperatures are high enough to
permit growth (cf. Chapter
). Attempting to use scionwood in which the
buds are starting active growth usually results in failure: the buds leaf-out
before the graft union is healed and water losses from these leaves cannot
be replaced so the scions dry out and die. Scionwood should therefore be
collected when dormant and, if it is not used immediately, stored in a cool
chamber at
◦
C or, if external conditions are cold enough, bundled and
heeled in on the shady side of a building.
-
When a high temperature is used for callusing bench grafts the material
should be collected in autumn and the grafts made before any cold weather
has overcome the rest (dormancy) requirement of the buds. After the union
is well healed the grafts must be stored at
◦
C to meet the winter-chilling
requirement of the buds and hold them dormant until planting (Howard and
Hildreth,
-
).
Effects of height of budding or grafting
on scion vigour and cropping
High budding, so as to give a greater length of rootstock stem, reduces the
vigour of the scion. This effect persists indefinitely on dwarfing rootstocks
but tends to diminish after a few years on vigorous rootstocks (Parry
;
van Oosten,
). With 'M.
' as a rootstock (Table
.
) the total extension
shoot growth over
years of 'Cox' budded at
mm was only
%of
that of 'Cox' budded at
%.
There was only a slight and non-significant reduction in cropping, so cropping
efficiency was greatly increased. The relative effect of high budding on vigour
of growth is much greater on 'M.
cm and that of 'Golden Delicious' was
' but this is accompanied
by undesirable fluting and burr-knot formation on the rootstock stem (Parry,
' than on 'M.
) showed that high budding of a vigorous pear scion on
'Quince A' rootstock reduced growth and increased precocity of cropping
compared with low budding.
). Blanco (
